1. Field of the Invention
The present invention relates to storage devices and methods, information processing apparatuses and methods, and provision media therefor, and in particular, to a storage device and method for providing a memory card capable of reading and writing data in which changes in a tuning frequency are suppressed, an information processing apparatus and method using the storage device and method, and a provision medium therefor.
2. Description of the Related Art
In recent years, memory cards, in which the storage capacity is greatly increased by providing semiconductor chips such as integrated chips for storing and processing information (data), have been widely used as data cards.
Also non-contact memory cards have recently been developed in which a built-in data-transmitting-receiving antenna circuit (coil) for transmitting or receiving an input or output radio signal is used to perform non-contact data reading and writing with an external processing apparatus by a radio system.
FIG. 14 shows the structure of a non-contact memory card 91. An antenna 101 included in the memory card 91 receives radio waves from a non-contact memory-card reader-writer 92 (described below), and supplies a signal corresponding to the received radio waves to a tuning circuit 102 and a power-supply circuit 111. The tuning circuit 102 extracts, from the signal supplied from the antenna 101, a carrier frequency used for communication between the memory card 91 and the reader-writer 92.
An amplifying circuit 103 amplifies an input signal to a predetermined level, and outputs the amplified signal. A demodulating circuit 104 demodulates the modulated signal having the carrier frequency into predetermined data. A communication control circuit 105 performs switching between data transmission and reception. A microcomputer 106 controls other blocks of the memory card 91 in accordance with a control program stored in a read only memory (ROM) 107. Among data supplied via the communication control circuit 105, data to be stored are supplied as required from the microcomputer 106 to an electrically erasable and programmable read only memory (EEPROM) 108.
The EEPROM 108 stores the data supplied from the microcomputer 106. A modulating circuit 109 modulates the data supplied from the communication control circuit 105 into a signal having the carrier frequency, and outputs it. An amplifying circuit 110 amplifies the modulated signal having the carrier frequency, supplied from the modulating circuit 109, to a level necessary for communication. The antenna 101 uses radio waves to transmit the carrier frequency signal amplified by the amplifying circuit 110.
FIG. 15 shows the structure of a non-contact memory-card reader-writer 92. An antenna 121 transmits a predetermined signal to the memory card 91 and performs transmission and reception of predetermined carrier waves in order to communicate with the memory card 91. The antenna 121 also generates an electromagnetic field for supplying power to the memory card 91.
A tuning circuit 122 extracts, from a signal supplied from the antenna 121, the carrier frequency used for communication between the memory card 91 and the reader-writer 92. An amplifying circuit 123 amplifies the input signal to a predetermined level, and outputs it. A demodulating circuit 124 demodulates the modulated signal having the carrier frequency into predetermined data. A communication control circuit 125 performs switching between data transmission and reception, and communication control. A microcomputer 126 controls other blocks of the reader-writer 92 in accordance with a control program stored in the ROM 128. Among the data supplied via the communication control circuit 125, data to be stored are supplied as required from the microcomputer 126 to a random access memory (RAM) 129.
The RAM 129 stores the data supplied from the microcomputer 126. A modulating circuit 130 modulates data supplied from the communication control circuit 125 into a signal having a carrier frequency, and outputs it. An amplifying circuit 131 amplifies the modulated signal having the carrier frequency, supplied from the modulating circuit 130, to a level necessary for communication. The antenna 121 uses radio waves to transmit the amplified signal having the carrier frequency.
The above-described conventional memory cards have a problem in that performance deteriorates since a tuning frequency varies due to variations in the quality of components.
Accordingly, it is an object of the present invention to provide a storage device and method in which the tuning frequency of a memory card is adjusted to prevent performance from deteriorating, an information processing apparatus and method using the storage device and method, and a provision medium therefor.
To this end, according to an aspect of the present invention, the foregoing object is achieved through provision of a storage device for storing and processing information and for performing information transmission and reception with an external unit. The storage device includes a storage unit for storing tuning-frequency data, an extracting unit for extracting a tuning frequency from a received signal, and an adjusting unit for adjusting, based on the tuning-frequency data stored in the storage unit, the tuning frequency extracted by the extracting unit.
According to another aspect of the present invention, the foregoing object is achieved through provision of a storage method for storing and processing information and for performing information transmission and reception with an external unit. The storage method includes the steps of storing tuning-frequency data, extracting a tuning frequency from a received signal, and adjusting, based on the tuning-frequency data stored in the storing step, the tuning frequency extracted in the extracting step.
According to a further aspect of the present invention, the foregoing object is achieved through provision of a provision medium for providing a program to a storage device for storing and processing information and for performing information transmission and reception with an external unit. The program causes the storage device to execute a process including the steps of storing tuning-frequency data, extracting a tuning frequency from the received signal, and adjusting, based on the tuning-frequency data stored in the storing step, the tuning frequency extracted in the extracting step.
According to a still further aspect of the present invention, the foregoing object is achieved through provision of an information processing apparatus for accessing a non-contact storage method. The information processing method includes the steps of extracting a tuning frequency from a received signal, adjusting the tuning frequency extracted in the extracting step, and storing data read from the non-contact storage device.
According to yet another aspect of the present invention, the foregoing object is achieved through provision of a provision medium for providing a program to an information processing apparatus for accessing a non-contact storage device. The program causes the information processing apparatus to execute a process including the steps of extracting a tuning frequency from a received signal, adjusting the tuning frequency extracted in the extracting step, and storing data read from the non-contact storage device.
According to the present invention, a tuning frequency is adjusted based on a stored tuning frequency, whereby performance can be prevented from deteriorating.